First of all, I would strongly advise against changing the input requirements for factories. If there is a factory type that is not profitable, there is usually a good reason for it that is related to supply and demand and efficiency. Given that my electric gear factories are always my best earners (even beating out cars and radios), the fact that yours are facing problems points to a market problem, not a game problem.
The #1 thing to look at first is whether you even have access to the inputs you need for the factories. If it is early enough, you may simply not be getting significant quantities of rubber. And even if all rubber events have fired, if you aren't #1 in the world, someone else might be buying up all the rubber before you get a chance to buy any. This is why one of my strategies is to conquer and colonize all areas that will have rubber in them eventually. If I own, I get to buy it and feed the gaping maw that is my factories.
I'd also think about whether your factories are efficient enough. If you have the rubber, and there is demand for electric gears, but the factories aren't profitable, then you need to look at the economic techs and industrial techs you have. If you are behind in economic techs that provide factory efficiency bonuses or you are behind in the power techs under industry, get those techs ASAP. The percentages on the economic techs seem small, but even a +2.5% increase in output efficiency can mean the difference between being profitable and going bankrupt. The input efficiency techs are also vital; that 1% reduction in input good demand makes a huge difference in the late game.
